OPERATION MANUAL CompoBus/S

Supplying Power to the Slaves Section 2-3
2-3-1 Using 2-conductor VCTF Cable
Independent Power Supplies
Master
H
L
+ –
Power cannot be supplied to the Slaves through 2-conductor VCTF cable.
When a CompoBus/S System is being constructed with 2-conductor VCTF
cable, each Slave must be supplied with power along a route separated from
the VCTF cable. Furthermore, an I/O power supply must be provided for
Slaves that require an I/O power supply.
2-conductor VCTF cable Multidrop (See note.)
H L
H L
H L H L
Slave Slave
–
+
For I/O
Slave
–
+
For I/O
Slave
Power
supply
Branch line
(See note.)
Common power supply for
communications and I/O
+ – + – + –
+ – + – + – + – + – + –
Network power supply
For
Communications
Power
supply
Communications
power supply
Power
supply
I/O power
supply
For Communications
Communications
power supply
Note Both T-branch connections and multidrop connections are possible with each
type of power supply.
Common Power Supply When using a common power supply with long power lines, make sure that
there isn’t a significant decline in the supply voltage due to attenuation.
Master
H
L
2-conductor VCTF cable Multidrop (See note.)
+ –
Power
supply
Branch line
Power
supply
I/O power
supply
Power
supply
Branch line
Common power supply for
communications and I/O
Multiple power supplies Local power supply
Branch line
(See note.)
Branch line Branch line
H L
H L
H L H L
Slave Slave
–
+
For I/O
Slave
–
+
For I/O
Slave
Common power supply for
communications and I/O
Network power supply
+ – + –
For Communications
Note that voltage will
For Communications
+ –
drop if the power supply
line is too long.
+ –
Power
supply
Power
supply
I/O power supply
Note Both T-branch connections and multidrop connections are possible with each
type of power supply.
Terminator
Terminator
It is possible to supply all communications power collectively via a single line.
If the power supply line is too long, however, the conductor resistance of the
cable will cause voltage to drop. For information concerning the allowable
length of the collective power supply cable, refer to 4. Cable Length Limit Due
+ –
+ – + –
Power
supply
I/O power supply
Power
supply
Common power supply for
communications and I/O
Multiple power supplies Local power supply
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